Whislt Steve is more than likely correct. Some owners changed from standard delivery rigging. It may be worth running a 10m tape measure up, tied or taped to a halyard.
Can find more info at Tophatyachts.com
They all do differ slightly, depending on who made the mast.
Michael's info is the best and how I have done so in the past.
Have you joined the Top Hat site sgturps?
You would have the answer now